Conventional winding units for winding strand materials, such as glass roving and the like, have a plurality of stations comprising a roving supply, guide/traverse means, and a spindle for taking up the strand material. Normally such units are maintained by a skilled operator who watches for filled spindles. When a filled spindle occurs, the machine stops. The operator then removes the filled package and then restarts the winding of the supply on an empty spindle. The winding unit can be closed down for periodic removal of the filled packages from each of the stations of the unit, followed by restarting of the winding operation. As a result of the mode of operation, the winding is more labor intensive than desired, and/or the winding units are not efficiently employed.
Automatic winding units have been described in the prior art. One example of an automatic unit utilizes turret-type spindles where the continuous winding switches from one spindle to another while retaining the strand end. The turret-type units are not intended for a discontinuous winding operation. Other automated units have been described wherein during the time when a full package from a spindle is doffed and winding restarted, the strand material is wasted. Moreover, spinning units such as described in Bell and Niederer, U.S. Pat. No. 3,398,521 patented Aug. 27, 1968, which is assigned to the predecessor of the assignee of the present application, are known wherein a yarn end is severed and then a bobbin rethreaded with the retained yarn end. In the described units the donning, doffing, and rethreading operation is relatively complex and not suitable for use in a winding unit.
Accordingly, there is a need for automatic winding units capable of servicing a discontinuous winding operation suitable for, inter alia, taking up glass roving wherein the speed and tension on the strand material must be maintained substantially uniform throughout winding, including during the automatic doffing of roving packages from filled spindles, rethreading, and restarting which provides a uniform product and is relatively simple in operation.